Fur -- I would use .2 mS on your sweep setting so we can see more detail of the wave form. I'm also beginning to wonder if the double trace image is related to the test conditions more than anything else. With literally EVERYTHING identical (scope channel, settings, cables, etc.), what happens if you test the other channel under the exact same test conditions? Does it show the same double trace wave forms and react to the volume control setting as these show?
Your transformer measurements are DC readings from your Ohmmeter. What is important to this discussion is the impedance of transformer, where impedance is a complex value expressed in Ohms, but includes resistance, capacitance, and inductance. It is often referred to as AC resistance as well. It is not hard or complicated to measure, and can be done with little more than your DVM -- but it is best done with the use of a variac. Do you have one?
Dave
Your transformer measurements are DC readings from your Ohmmeter. What is important to this discussion is the impedance of transformer, where impedance is a complex value expressed in Ohms, but includes resistance, capacitance, and inductance. It is often referred to as AC resistance as well. It is not hard or complicated to measure, and can be done with little more than your DVM -- but it is best done with the use of a variac. Do you have one?
Dave